The book, which comes out Tuesday, alleges that the singer went with Armstrong to Belgium and witnessed a procedure in 2004.

"Rather than try to hide the transfusion from her, Armstrong was completely open about it. He trusted that Crow would have no desire to tell the press or anyone else about the team's doping program. He explained that it was simply part of the sport -- that all cyclists were doing the same thing," Albergotti and O'Connell write, according to the New York Daily News.

Crow and Armstrong dated in 2003, got engaged in 2005 and broke up in 2006.